Some of my hollyhock leaves have little holes all over them. What pests are...

Asked June 1, 2014, 7:27 PM EDT

Some of my hollyhock leaves have little holes all over them. What pests are causing this and what can I do to eradicate them? I am certain it is not caterpillars since the holes are tiny AND leave a "lacy" appearance on the leaf.

Hennepin County Minnesota

1 Response

While it's early in the year for many hollyhock problems to show up, there are a few that you may be able to identify now. Here is a response to a very similar question posted by one of our AaE volunteers:

Several things can skeletonize hollyhock leaves: 1. Hollyhock sawfly (tiny green worms that feed on the undersides of the leaves). It's easy to miss them. Learn more here: 2. Hollyhock rust. Note these comments about rust from a University of Minnesota bulletin: "Infection first occurs on the lower leaves and then progresses upward to involve the entire plant. Initial symptoms of hollyhock rust are yellow to orange spots on upper leaf surfaces and brown, elongate lesions on the stems. Later, red to brown pustules develop on the lower surface of infected leaves. Orange-red spores are released from the pustules and rain splashed or wind blown to nearby leaves, starting new infections throughout the summer. Eventually, leaf spots brown and drop out leaving holes. Severely infected leaves turn brown and dry." When many of the spots drop out, the result is often a lace-like effect. Look for the brown pustules on the undersides of the leaves. They show up before the lacy pattern develops. Learn more here: 3. Japanese beetles. These beetles are hard to miss, so it should be easy to tell if they are doing the damage. __________ You can divide tulip and daffodil bulbs after the foliage matures. Do it soon after that (probably in early to mid-summer) while the dead or dying foliage still marks the bulbs' location. Also note this information from a University of Vermont bulletin: "Lift the bulbs carefully, free them from soil, remove the tops, pull them apart, and replant immediately. If not replanted at once, they may be washed, spread in an airy and shady place to dry, and then stored in shallow boxes in a cool, dry, airy place until planting time the following fall."
Bob Minnesota Master Gardener